Post by: RGP750 on May 10, 2023, 03:11:55 PM
I have a problem with my 72 500/4.Went out on it last year and everything perfect.
This year turn on ignition and dead short somewhere, frustrating nightmare.
Gradually disconnected areas of wiring, handlebar switches, rear light, horn regulator, etc and finally every connector in the headlight.
Thought it could be solenoid so replaced that, bypassed ignition switch , still doing it . any thoughts pleeeeeeeese!
Rich
Post by: McCabe-Thiele (Ted) on May 10, 2023, 03:33:20 PM
So does it blow the fuse as soon as you switch the ignition on?
Have you done any work on the bike since you lay her up for the winter?
Is the regulator/ rectifier standard?
Post by: paul G on May 10, 2023, 03:36:24 PM
Reconnect the red and white wires one at a time and then the black wires one at a time until you find the problematic item section.
This will help to narrow it down.
You can also check the other side of the black wire connections for continuity to earth.
Post by: RGP750 on May 10, 2023, 04:05:35 PM
I have disconnected every wire I can think of and it still blows as soon as I turn the key, or cut out the switch and " hot wire-"
If I got to the situation when the fuse didn't blow I could start adding wires until it went again but not there yet.
What else can I disconnect?
Post by: Nurse Julie on May 10, 2023, 04:11:21 PM
Post by: Toko_Jo on May 10, 2023, 04:19:34 PM
Post by: RGP750 on May 10, 2023, 04:38:06 PM
Yes correct fuse fitted .
As I have said it ran perfectly last year and something has gone ary while standing .
Just don't know where to look now.
Nbefore getting silly and replacing everything again
Post by: Oddjob on May 10, 2023, 04:46:46 PM
Post by: Bryanj on May 10, 2023, 05:03:25 PM
It melts inside the loom all the way along destroying other wires.
If thats ok first things i would disconnect are rectifier and regulator
Post by: Oddjob on May 10, 2023, 05:11:52 PM
Post by: Toko_Jo on May 10, 2023, 05:45:29 PM
Post by: RGP750 on May 10, 2023, 05:51:38 PM
Already removed the regulator and andrectifier.
It really is looking at taking the loom off and seeing if I can find anything. Cheers all
Post by: Nurse Julie on May 10, 2023, 06:05:40 PM
Brand new loom fitted last year when I gave it a tidy up .
Yes correct fuse fitted .
As I have said it ran perfectly last year and something has gone ary while standing .
Just don't know where to look now.
Nbefore getting silly and replacing everything again
Mine was originally a new aftermarket loom from DSS the year before Rich. Graham put another new loom on, changed the ignition switch and the sub loom. Never did find what part was at fault because i just wanted to ride her once she was running.
Post by: Laverdaroo on May 10, 2023, 06:22:36 PM
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Post by: RGP750 on May 10, 2023, 06:39:21 PM
Post by: McCabe-Thiele (Ted) on May 10, 2023, 06:55:31 PM
I'm racking my brains as to what could deteriorate as it has stood over the winter - it seems unlikely that a wire could chafe or that an alternator wire would somehow become disconnected and short as it has stood.
My only ever experiences of a similar type of problem was when a rectifier had rusted causing a short in the casing & when a regulator stuck - two separate episodes first one on a bike, the second on a car.
My suspicion is that if such a failure has blown a number of fuses it is likely that wiring in the loom has overheated leading to further dead short. I mention this as if something has caused the loom to fail replacing the loom could lead to another loom failure.
Not sure if it is possible that major internal battery cell failure could be a cause?
Might be worth checking the state/condition of the battery.
Post by: RGP750 on May 11, 2023, 07:12:01 AM
Motobatt , seems fine.
I took the loom off last night and externally looks fine I assume I have to unwrap it to check every wire.
That's the bit I can't get my head around , it was running fine
Post by: paul G on May 11, 2023, 07:48:28 AM
Post by: Toko_Jo on May 11, 2023, 07:50:22 AM
Thanks for your thoughts. Battery off over winter on optimiser.
Motobatt , seems fine.
I took the loom off last night and externally looks fine I assume I have to unwrap it to check every wire.
That's the bit I can't get my head around , it was running fine
Like I said in my previous reply, do a continuity check between any black wires and green. When you do that flex the loom at the same time with the meter still connected to see if there is continuity at anytime.
Failing that, you could sent it to that nice chap Ash on here..pretty sure he could check it out...sure he wouldn't mind :)
Post by: Bryanj on May 11, 2023, 08:38:52 AM
Post by: McCabe-Thiele (Ted) on May 11, 2023, 11:30:57 AM
Normally the right hand side of the battery is the Negative terminal when fitted to the bike.
An earth lead goes from this Negative terminal to the engine.
The left side as you look at the battery is Positive and has a connection for the live side.
The battery on my 400 was fitted back to front when I bought the bike so both terminals were close to the frame. The earth lead had been attached to the rectifier mounting bolt.
My apologies in advance I do not want to offend anyone reading this post. I did wonder if any additional wires had been connected to the live side that might have been left off and caused a short circuit. My bike has an additional permanent fused cable on the live side connected to a special charging plug for my C-tek unit and to a volt meter I have fitted.
Just thinking of any possible reason why all that has changed is you have had the battery out over the winter and now it's faulting.
Post by: taysidedragon on May 11, 2023, 11:36:12 AM
Post by: RGP750 on May 11, 2023, 07:15:33 PM
As for other suggestions. Yes battery is the right way around
The plug it in and one at a time theory is great if the fuse doesn't blow but as its still blowing it won't find it.
Still head scratching cheers
Post by: Oddjob on May 11, 2023, 07:23:00 PM
In which case as Jo says, a simple test between black and green should show if it is the loom.
Post by: RGP750 on May 11, 2023, 07:30:19 PM
Post by: robvangulik on May 11, 2023, 09:57:08 PM
Thanks Toko Jo I know Ash , I'll give him a call.Replacing the fuse with a lightbulb makes fault finding much easier (and cheaper, doesn't cost so many fuses.)
As for other suggestions. Yes battery is the right way around
The plug it in and one at a time theory is great if the fuse doesn't blow but as its still blowing it won't find it.
Still head scratching cheers
Post by: McCabe-Thiele (Ted) on May 11, 2023, 11:22:21 PM
Post by: K2-K6 on May 12, 2023, 09:46:25 AM
I am baffled as to how the fault has developed Rich - I for one will be very interested as to the cause of problem when you identify it. Iirc it was a new loom as well.🤔
All wiring is capacity, doesn't melt under designed for load. And insulation, to prevent leaking into something else. Well that's the simplified way I look at it.
So, either overloaded with excess or too small to handle the task reasonably. Or, damaged physically, the insulation, to be insufficient in stopping leaking to give overload.
Checking any multi plugs first to make sure there's no obvious breach to catch you out is worthwhile.
Post by: Oddjob on May 12, 2023, 03:43:34 PM
Post by: K2-K6 on May 12, 2023, 05:03:56 PM
The throttle cable and clutch cable had both melted their outside plastic covers ! Slow and difficult starting too, he'd left the earth strap off to the engine block after working on it, using starter had then tracked down those two routes in scavenging earth supply to crank it :)
Damned leaky stuff yer electrick-tricity ;D it'll get out with any slight chance offered.
Post by: RGP750 on May 12, 2023, 07:10:30 PM
Well I took everything off I could find including the battery.
Did the continuity green?black test on the loom and couldn't find anything. Put loom back on and
fuse NOT BLOWING ,put together rear light wiring , tested , Ok switches OK horn ok everything else all ok .
A eureka moment fuse still ok . Now here is the next problem , what the hell is wrong now. Nothing works :-\
no horn, starter, dash lights rear light Nothing. What the hell have I missed. HELLLLP!!!!!
Done Battery test and 12v
Post by: SteveW on May 12, 2023, 07:15:37 PM
Post by: RGP750 on May 12, 2023, 07:18:33 PM
Please see the start of the thread cheers
Post by: K2-K6 on May 12, 2023, 07:49:58 PM
Post by: RGP750 on May 12, 2023, 08:16:48 PM
Post by: K2-K6 on May 12, 2023, 08:31:24 PM
Positive lead to fuse exit, negative lead to battery -
Post by: RGP750 on May 12, 2023, 08:38:31 PM
Just found out why nothing working, knew it would be something stupid OOPs! multi plug on the loom not plugged in :-[
But now I have plugged it in Fuse has blown so where to look now.
Post by: K2-K6 on May 12, 2023, 10:08:16 PM
If there's nothing obvious, and it still blows the fuse when nothing is connected (any devices) to influence the outcome, then it must have some compromise inside.
Post by: RGP750 on May 12, 2023, 10:21:29 PM
Post by: Bryanj on May 13, 2023, 07:50:55 AM
Post by: RGP750 on May 13, 2023, 08:11:13 AM
Disconnect block, check black live into headlight for continuity and all is fine , plug block in and it shorts.
I then check black in sub loom and ok, check black on regulator ok. Something is happening when it is plugged in .????¿
Post by: McCabe-Thiele (Ted) on May 13, 2023, 10:00:24 AM
Have you tried it with just the rectifier plug disconnect & the flasher unit not connected?
Post by: RGP750 on May 13, 2023, 04:40:51 PM
I have ordered a new one and will report back.
Looks like Ted may get first prize.
Watch this space
Cheers all for your thoughts.
Post by: McCabe-Thiele (Ted) on May 13, 2023, 07:16:08 PM
.(https://live.staticflickr.com/65535/51917764175_d0a5d5d5a0_o.jpg) (https://flic.kr/p/2n6N7v6)flasher unit (https://flic.kr/p/2n6N7v6) by Macabe Thiele (https://www.flickr.com/photos/187487200@N03/), on Flickr
Post by: RGP750 on May 13, 2023, 07:41:30 PM
Post by: McCabe-Thiele (Ted) on May 13, 2023, 07:57:53 PM
Post by: RGP750 on May 14, 2023, 07:04:19 AM
Post by: McCabe-Thiele (Ted) on May 14, 2023, 08:38:47 AM
Post by: K2-K6 on May 14, 2023, 09:42:17 AM
If so, well spotted Ted :)
Post by: RGP750 on May 14, 2023, 06:12:53 PM
hope the new one works ok. I would have liked an original but can't find one.
Cheers Rich
yes well done Ted, I owe you one.
Post by: RGP750 on May 16, 2023, 07:54:24 PM
New flasher relay fitted , fuse didn't blow,
Eureka.
Next problem the lights
Don't flash :'( any thoughts please.
Post by: Oddjob on May 16, 2023, 11:27:23 PM
First thing to check if so, is the blue wire actually connected in the headlight?
Post by: RGP750 on May 17, 2023, 06:50:00 AM
Headlight is fine main and dip. . I don't have a headlight flash button .
Right indicator turns front and rear indicators but not flashing and left is the same .
I have tried another different unit and it's the same ?????
Post by: Oddjob on May 17, 2023, 06:56:55 AM
Sounds like a bad earth, have you tried running a wire from the indicators to a good earth point?
A UK CB500 should have a headlight flasher Rich, is it an import?
Post by: RGP750 on May 17, 2023, 07:16:24 AM
All 4 indicators are earthed , I'll try another new earth thanks .
Not an import it's a k1 from Steve admin.
Post by: McCabe-Thiele (Ted) on May 17, 2023, 08:42:00 AM
If it is you may need to reverse the connections as one way the flashing circuit does not operate.
Post by: RGP750 on May 17, 2023, 12:50:03 PM
Post by: McCabe-Thiele (Ted) on May 17, 2023, 03:00:26 PM
3 terminal as previous one.
Are you using conventional Tungsten bulbs of the correct wattage or LED's?
Is it an electronic flasher unit that works at a fixed rate irrespective of the bulb load?
Are the terminals marked differently - I suspect it might just back to front on the flashing circuit - leave the earth circuit as it is & try switching the terminals - for safety you can add a bulb type circuit test to remove any chance of blowing the flasher unit?
It will not flash if its a standard flasher unit with LED bulbs or if the bulb wattage is too low - sometimes you get a hyper fast flashing rate instead.
Post by: RGP750 on May 17, 2023, 05:19:32 PM
a new relay (well 2 actually both different makes) .I have tried reversing the black and grey and same result with both relays.
God I hate electrics
Post by: McCabe-Thiele (Ted) on May 17, 2023, 05:42:27 PM
When I replaced the flasher unit in my 400 I could not find the ones with three terminals so fitted a two terminal unit.
I am thinking that you might have the later car type flasher unit they will be marked with an earth designed for modern cars that are positive earth.
Post by: Oddjob on May 17, 2023, 05:43:02 PM
Electrics are easy, I kinda like doing them, it's just having a logical approach and persevering. It's when it goes internal on generators etc that I lose interest. Wiring though, I quite like.
Post by: Bryanj on May 17, 2023, 05:58:54 PM
Post by: McCabe-Thiele (Ted) on May 17, 2023, 06:29:45 PM
If so I think it must be related to your flasher relay.
Post by: RGP750 on May 17, 2023, 09:28:09 PM
Ted I have used 2 relays , both new and different makes with the same result.
Post by: McCabe-Thiele (Ted) on May 17, 2023, 10:18:39 PM
Thanks Brian I'll give that a try tomorrow.Yes but are they the correct part you have fitted?
Ted I have used 2 relays , both new and different makes with the same result.
As someone here has posted earlier if you bridge those two wires (not the earth) can you make them flash on and off by breaking and making the connection the connection? If it's yes you know where the answer lies. I'm not great with electrics and have no idea how a two terminal flasher really works but it does.
Post by: McCabe-Thiele (Ted) on May 17, 2023, 10:19:26 PM
Thanks Brian I'll give that a try tomorrow.Yes but are they the correct part you have fitted?
Ted I have used 2 relays , both new and different makes with the same result.
As someone here has posted earlier if you bridge those two wires (not the earth) can you make them flash on and off by breaking and making the connection? If it's yes you know where the answer lies. I'm not great with electrics and have no idea how a two terminal flasher really works but it does.
Post by: RGP750 on May 19, 2023, 01:50:52 PM
I gave up on the 2 flasher units I bought, one on eBay and one from a local motor factors, (Lucas for M/C)
got a NOS Honda one from a mate , all is well going for a ride later.
Thanks for all of your input.
Rich
Post by: McCabe-Thiele (Ted) on May 19, 2023, 02:08:31 PM
Post by: Oddjob on May 19, 2023, 03:45:45 PM
There is an alternative used in the US market, where we got a round relay they got a oblong or square one, rubber mount is then square, 38306-107-670 and the square relay, 2 pin version is now 38301-KJ6-741/2/3